What things control population?

Answer 1

Population as a growth rate in animals is controlled by the available resources, but is influenced by factors such as changes in climate, disease, and predation.

For humans, population growth is limited by the supply of food and land to grow it on, and by the technological capacity to provide services. However, human populations have grown even when resources were scarce, as a response to the value of additional labor. Families at the subsistence level will have more children as a response to a high rate of child mortality. In human history, both famine and war have been major influences on population.